Human physical capacity is the maximal ability of the body to perform physical work. It is the basis for all physical activity, but until now, has never been measured. To measure human physical capacity would require a dynamometer capable of simultaneously working all four limbs of the body through a full range of motion while maximally loading the muscles through a full range of speeds, but until now, no such dynamometer existed.
Conventional dynamometers measure torque and angular velocity of rotating devices like automobile engines in order to calculate power (torque×angular velocity=power). But human limbs don't rotate; they reciprocate in an angular manner and to measure them would require a dynamometer capable of capturing the reciprocating torques and reciprocating angular velocities of reciprocating limbs. If, in addition, such a dynamometer was capable of adjusting to provide similar ranges of motion for limb joints of human users of different body height and limb length, a noninvasive reflection of muscle composition (fiber typing) would also be possible.
Such a dynamometer would express human physical capacity as the sum of the physical capacities of the four limbs, the physical capacity of each limb expressed as a plot of cyclical moving average of power (hereinafter called “cyclical power”) over cycle frequency from which peak cyclical power and the corresponding cycle frequency at peak cyclical power would be identified. Peak cyclical power would be the maximal rate of work performed, averaged over one movement cycle. Cycle frequency at peak cyclical power would be a noninvasive reflection of muscle composition, revealing the unique blend of underlying, inheritable, yet trainable, metabolic energy pathways supporting the strength, speed and power of that limb. Fundamental to the expression of human physical capacity would be use of moving averages based not on time, but on movement cycle.
Such a dynamometer would: (1) identify peak cyclical power of the human body by simultaneously assessing the peak cyclical powers of the four limbs, providing a side by side comparison of left arm versus right arm, left leg versus right leg, left side of body versus right side of body, upper body versus lower body or the sum of all four limbs for a comparison involving the entire body; (2) identify cycle frequency at peak cyclical power for each limb as a noninvasive reflection of the muscle composition of that limb, revealing the unique blend of underlying, inheritable, yet trainable, metabolic energy pathways supporting the strength, speed and power of that limb; (3) establish normal ranges for peak cyclical power and the corresponding cycle frequency at peak cyclical power for specific human populations, with linear regressions for height, weight, age, sex, muscle composition, etc., for use in normalizing the impact of individual physical differences and enabling a meaningful discussion of a subject's current physical capacity and potential for improvement; (4) encourage new strength, speed and power research and thereby elevate anaerobic training to a level of credibility similar to aerobic training in the research literature; and (5) provide a safe, maximally intense, full range of motion and speed, exercise testing activity for individuals of any height, weight, age, sex, muscle composition, athletic ability, etc., and thereby enable them to witness the health benefits and structural and physiologic changes associated with strength, speed and power training.
With no such dynamometer and therefore no measure of human physical capacity, exercise research has been limited to aerobic testing despite the fact that aerobic capacity represents less than one third of human physical capacity. Nevertheless, the ability to measure oxygen uptake has given aerobic, cardiovascular endurance exercise a level of credibility well beyond that of anaerobic, strength, speed and power exercise even though sustained, repetitive, aerobic activities decrease flexibility, compromise lifesaving peripheral vascular and pulmonary reflexes, alter cardiac morphology to that seen in congestive heart failure and cause a disproportionate number of sudden cardiac deaths. Even the health benefits of aerobic exercise could be the result of unmeasured changes in strength, speed and power rather than changes in endurance. If available, a reciprocating dynamometer to assess human physical capacity and muscle composition would shed new light on these issues and add a new and long awaited perspective to this debate.
With no such dynamometer and therefore no noninvasive indicator of muscle composition, athletes have undergone muscle biopsies to determine their muscle compositions despite the damage done to otherwise healthy muscle tissue and the fact that muscle composition varies from muscle to muscle and limb to limb within the same individual. If available, a reciprocating dynamometer to assess human physical capacity and muscle composition would provide an alternative to muscle biopsies, namely, a plot of cyclical power over cycle frequency from which the corresponding cycle frequency at peak cyclical power would be identified for each limb, reflecting the muscle composition of that limb and unique blend of underlying, inheritable, yet trainable, metabolic energy pathways supporting the strength, speed and power of that limb.
With no such dynamometer, animal research using isolated muscle tissue preparations to study muscle physiology has had difficulty moving from theory to practice without a corresponding in vivo technique to study intact human muscles. If available, a reciprocating dynamometer to assess human physical capacity and muscle composition would demonstrate in maximally exercising human subjects, physiologic activity that, until now, has only been demonstrable in animal models.
With no such dynamometer, scholastic athletic programs have supported gifted athletes while less talented individuals become discouraged and drop out. If available, a reciprocating dynamometer to assess human physical capacity and muscle composition would introduce a new form of athletic competition in which a contestant's physical capacity test score is analyzed using linear regressions for height, weight, age, sex, muscle composition, etc., in order to normalize the impact of individual physical differences and statistically level the playing field so that anyone of any height, weight, age, sex, muscle composition, etc., could compete head to head with anyone else relative to their own physical potential and experience the challenge of reaching that potential.
With no such dynamometer, metabolic decline from youth to old age has been relentless, with progressive loss of strength, speed and power a recognized and sensitive biomarker of aging. If available, a reciprocating dynamometer to assess human physical capacity and muscle composition would challenge prevailing assumptions about exercise and aging, giving antiaging and longevity researchers a new technology with which to identify and combat causes and consequences of aging.
In summary, human physical capacity and muscle composition have eluded scientific measure because of an absence of dynamometers capable of: (1) simultaneously working all four limbs of the body through a full range of motion while maximally loading the muscles through a full range of speeds; (2) simultaneously capturing the reciprocating torques and reciprocating angular velocities of all four reciprocating limbs, and (3) adjusting to provide similar ranges of motion for limb joints of human subjects of different body height and limb length. As a result, advances in exercise physiology, healthcare, athletics and anti-aging/longevity research have been compromised. The present reciprocating dynamometer to assess human physical capacity and muscle composition addresses these issues.
The following works of others are hereby incorporated in their entirety by reference:    1. 2nd Annual Duke Sports Cardiology & Sudden Death In Athletes Summit, Mar. 28, 2015, all presentations available on YouTube;    2. 1st Annual Duke Sudden Cardiac Death In Athletes Symposium, Apr. 12, 2014, all presentations available on YouTube;    3. Exercise Physiology for Health, Fitness, and Performance, Fourth Edition, by Plowman and Smith (copyright 2014);    4. Physiology of Sport and Exercise, Fifth Edition, by Kenney, Wilmore and Costill (copyright 2012);    5. Olympic Textbook of Science in Sport, IOC, edited by Maughan (copyright 2009);    6. Strength and Power in Sport, Second Edition, IOC, edited by Komi (copyright 2003);    7. The Olympic Book of Sports Medicine, First Edition, IOC, edited by Dirix, Knuttgen and Tittel (copyright 1988);    8. Physiology of Exercise, Third Edition, by deVries (copyright 1980);    9. Textbook of Work Physiology, Second Edition, by Astrand and Rodahl (copyright 1977).